Bacteriophage CP-T1 of Vibrio cholerae. Identification of the cell surface receptor

The attachment site on the cell surface of Vibrio cholerae for the bacteriophage CP-T1 has been determined. Purified lipopolysaccharide from the Inaba and Ogawa serotypes, and of both the Classical and El Tor biotype of strains of V. cholerae show equal phage-inactivating capacities. Lipopolysaccharide extracted from a CP-T1-resistant mutant has no phage-inactivating capacity. Such mutants lack O-antigen as demonstrated by bactericidal assays utilizing a monoclonal antibody directed against O-antigen side chain of V. cholerae lipopolysaccharide. Radiolabelling of lipopolysaccharide with 33P and analysis by sodium dodecyl sulfate/polyacrylamide gel electrophoresis also revealed the absence of O-antigen in phage-resistant strains. A number of V. cholerae typing phage show cross-resistance with phage CP-T1.